Objective—To assess the anesthetic efficacy and local tolerance of topically applied 0.4% oxybuprocaine ophthalmic solution to in dogs and compare its effects with those of 1% tetracaine solution. Animals—34 ophthalmically normal Beagles. Procedures—Dogs were assigned to 2 groups, and baseline corneal touch threshold (CTT) was measured bilaterally with a Cochet-Bonnet aesthesiometer. Dogs of group 1 (n = 22) received a single drop of 0.4% oxybuprocaine ophthalmic solution in one eye and saline (0.9% NaCl) solution (control treatment) in the contralateral eye. Dogs of group 2 (n = 12) received a single drop of 0.4% oxybuprocaine ophthalmic solution in one eye and 1% tetracaine ophthalmic solution in the contralateral eye. The CTT of each eye was measured 1 and 5 minutes after topical application and then at 5-minute intervals until 75 minutes after topical application. Results—CTT changes over time differed significantly between oxybuprocaine-treated and control eyes. After instillation of oxybuprocaine, maximal corneal anesthesia (CTT = 0) was achieved within 1 minute, and CTT was significantly decreased from 1 to 45 minutes, compared with the baseline value. No significant difference in onset, depth, and duration of corneal anesthesia was found between oxybuprocaine-treated and tetracaine-treated eyes. Conjunctival hyperemia and chemosis were detected more frequently in tetracaine-treated eyes than in oxybuprocaine-treated eyes. Conclusions and Clinical Relevance—Topical application of oxybuprocaine and tetracaine similarly reduced corneal sensitivity in dogs, but oxybuprocaine was less irritating to the conjunctiva than was tetracaine.

Objective-To assess the biological response to recombinant feline interferon-omega (rFeIFN-omega) following ocular or oral administration in cats via estimation of Mx protein expression in conjunctival cells (CCs) and WBCs. Animals-10 specific pathogen-free cats. Procedures-In multiple single-dose drug experiments, each cat received various concentrations of rFeIFN-omega administered topically into both eyes (50 to 10,000 U/eye) and orally (200 to 20,000 units). The same cats received saline (0.9% NaCl) solution topically and orally as control treatments. The CCs and WBCs were collected prior to treatment (day 0), on day 1, and every third or seventh day thereafter until samples yielded negative results for Mx protein. Samples were examined for Mx protein expression via immunohistochemistry and immunoblotting procedures involving murine anti-Mx protein monoclonal antibody M143. Results-After topical application of 10,000 U of rFeIFN-omega/eye, CCs stained for Mx protein for a minimum of 7 days, whereas WBCs were positive for Mx protein for a minimum of 31 days. After topical application of lower concentrations, CCs did not express Mx protein, in contrast to WBCs, which stained for Mx protein at 1,000 units for at least 1 day. Following oral administration, Mx protein was expressed in WBCs at rFeIFN-omega concentrations as low as 200 units, whereas CCs did not stain for Mx protein at any concentration. Conclusions and Clinical Relevance-Results indicate that Mx protein expression (a marker of the biological response to rFeIFN-omega) in CCs and WBCs of rFeIFN-omega-treated cats depends on the dose of rFeIFN-omega, site of administration, and cell type.

The effects of mitomycin-C on intraocular pressure (IOP), facility of outflow (C), and Tenon's capsule fibrosis were studied over 60 days in 10 clinically normal dogs. A 1-piece, silicone glaucoma implant was surgically implanted into both eyes; the filtration site of one eye was treated with a single, 5-minute intraoperative application of mitomycin (0.5 mg/ml), and the fellow eye was treated in a similar manner with balanced salt solution. There were no significant differences in preoperative IOP or C-values between treatment groups. Mean IOP in eyes of both groups initially decreased from the preoperative value, but returned to the baseline value by day 21. Mean facility of aqueous outflow (C-value) increased in all eyes during the first 14 days (mitomycin-C-value = 2.26 +/- 0.72; control C-value = 2.38 +/- 0.81), then reached a plateau that was significantly higher than the baseline value in mitomycin (P = 0.039) and control (P = 0.041) eyes. Histologic evaluation revealed all implants surrounded by a connective tissue capsule composed of regular dense collagen and fibroblasts that was significantly (P = 0.003) thinner in the mitomycin-treated (scleral side = 167 +/- 62 micrometer; conjunctival side = 122 +/- 41 micrometer) than the control (scleral side = 261 +/- 92 micrometer; conjunctival side = 180 +/- 48 micrometer) group. There were, however, no significant differences in IOP or C-values between groups at any postoperative time interval. Results of this study indicate that intraoperative treatment with mitomycin suppresses, but does not prevent fibrosis around silicone filtering implants.

The relationship between the palpebral conjunctival oxygen index, mixed venous oxygen tension, and cardiac index were compared, using a canine hemorrhagic shock model. The cardiac output was reduced by reducing the blood volume in 5% increments until the initial cardiac output was reduced by one half. In each of 7 dogs, the palpebral conjunctival oxygen index and mixed venous oxygen tension were found to have good correlation with cardiac index; however, the correlation coefficients were markedly reduced when the data from all of the dogs were combined. It was concluded that the palpebral conjunctival oxygen index provides an excellent means of assessing changes in cardiac index over time in the same dog; however, it cannot be used to estimate cardiac index in an individual dog with a degree of accuracy that would be clinically significant.

Conjunctival swab specimens from healthy pigs were cultured to determine normal microbial population. Four commercial swine operations were selected for study. Pigs of 4 age groups were tested: nursing pigs, nursery pigs, feeder pigs, and sows. Swab specimens were taken from the conjunctival sac of each pig. Bacterial, fungal, and mycoplasmal growth was determined separately. Chlamydia sp was detected by use of an ELISA. Bacteria were recovered from 98% of specimens evaluated. alpha-Streptococcus sp (89%) was the most commonly recovered organism, followed by Staphylococcus epidermidis (39%) and Staphylococcus sp (39%). Mycoplasma sp was not detected in any of the specimens. Chlamydia sp was identified in 28% of all specimens evaluated. These results are similar to reports of normal conjunctival flora in other domestic animals.

Conjunctiva-associated lymphoid tissue (CALT) in the eyelids of chickens was studied by gross, histologic, and electron microscopic techniques. Structural features were characterized at 1 day of age and at posthatching week (PHW) 1, 2, 3, 4, 6, 8, 12, and 16. Beginning at PHW 1, prominent lymphoid nodules containing a heterogenous population of lymphocytes, lymphoblasts, and macrophages were first observed within conjunctival folds and fissures of the lower eyelid. Nodules contained germinal centers by PHW 2 and plasma cells by PHW 4. The epithelium associated with these nodules was flat, had short, irregular microvilli, contained intraepithelial lymphocytes, and lacked goblet cells. High endothelial venules were located at the base of lymphoid nodules and contained lymphocytes within and below the cuboidal endothelium. In the upper eyelid, CALT was morphologically similar to lymphoid tissue in the lower eyelid, but nodules were smaller and more random, lacked association with epithelial folds and fissures, and were clustered around the opening of the nasolacrimal duct. By PHW 12, CALT was characterized by basal germinal centers outlined by collagenous stroma, suprafollicular plasma cells, columnar epithelium with goblet cells, and fewer intraepithelial lymphocytes. On the basis of these features, CALT in chickens has morphologic characteristics similar to other components of the mucosal immune system and, therefore, may have a role in mucosal immunity.

An experimental model of keratoconjunctivitis sicca (KCS) was produced by removing the lacrimal gland and the gland of the third eyelid from the left eye of 6 cats. The right eye of each cat was left intact and used as a control. After 2 weeks, cats were euthanatized and the central portion of the upper eyelid from both eyes of each cat was excised. Histologic sections were stained with either hematoxylin and eosin or with a battery of biotinylated lectins including concanavalin A (conA), soybean agglutinin (SBA), wheat germ agglutinin (WGA), succinylated wheat germ agglutinin (S-WGA), Ulex europaeus agglutinin I (UEA), Dolichos biflorus agglutinin (DBA), Ricinus communis agglutinin (RCA), peanut agglutinin (PNA), and PNA pretreated with neuraminidase. Consistent differences in histologic features were not observed between conjunctivas with KCS and control conjunctivas. A variable degree of mononuclear cell infiltration of the substantia propria was observed in control conjunctivas and those with KCS. In both groups, conjunctival goblet cell density decreased and epithelial stratification increased as the degree of submucosal inflammatory cell infiltration increased. Lectin binding sites for DBA, WGA, S-WGA, UEA, PNA, and PNA pretreated with neuraminidase were detected on conjunctival goblet cells of conjunctivas with KCS and control conjunctivas. The mucus/glycocalyx layer of conjunctival epithelial cells in both groups of conjunctivas bound lectins RCA, WGA, UEA, and conA, but inconsistently bound S-WGA. In both groups, DBA principally bound to the mucus layer overlying normal epithelium, whereas PNA pretreated with neuraminidase consistently bound to the mucus layer of stratified epithelial surfaces free of goblet cells. Binding of SBA to goblet cells and the mucus/glycocalyx layer was variable.

Objective-To investigate shedding of chlamydiae from conjunctiva and genital tracts of cats without clinical signs of conjunctivitis or other infectious disease in relation to their titers of serum antibodies against chlamydiae and to serum amyloid A (SAA) and serum alpha1-acid glycoprotein (AGP) concentrations. Animals-62 healthy cats. Procedures-Serum from each cat was analyzed for antibodies against chlamydiae and for SAA and AGP concentrations. Swab samples from the conjunctival sac and genital tract were analyzed with a real-time PCR assay for Chlamydiaceae. Results-4 of 8 of cats with high antibody titers (ie, 1,600) shed chlamydiae, but only from the conjunctiva. Chlamydiae could not be detected in samples from cats with lower antibody titers nor from any genital tract samples. In cats with antibody titers of 1,600, mean +/- SD SAA concentration was significantly higher when chlamydiae were detected in conjunctival swab samples (3.9 +/- 1.0 mg/L) than when no chlamydiae were detected (1.4 +/- 1.0 mg/L). However, SAA concentration was greater than the limit for an acute-phase response in only one of those cats. There was no significant difference in serum AGP concentrations between cats with high titers that were or were not shedding chlamydiae. Nine of 30 (30%) cats (5 with and 4 without detectable serum antibodies against chlamydiae) that had been mated developed reproductive disorders. Conclusions and Clinical Relevance-Clinically normal cats with high chlamydiae-specific antibody titers can shed and thus transmit chlamydiae. Venereal spread from cats without clinical signs of infection is likely not common.

Swab specimens for fungal isolation were collected from the healthy conjunctival sacs of 3 species of captive camelids (Lama glama, L guanicoe, L pacos) and llama-guanaco hybrids. Fungi were collected from over half the animals in winter (53%) and summer (56%). Fungal species of 10 genera were isolated. In both seasons, Aspergillus was the most commonly isolated genus; at least 9 species of Aspergillus were found. The fungal organisms isolated were similar to those found in healthy eyes of other domestic animals and may represent a random seeding from the environment where they are ubiquitous.

Healthy conjunctival sacs of 88 animals of 3 species of captive camelids (Lama glama, Lama guanicoe, Lama pacos) and llama-guanaco hybrids were sampled for bacterial and mycoplasmal flora. Mycoplasmas were not isolated from any animal. Eleven genera of bacteria were isolated. The most frequent isolates were Staphyloccus epidermidis and Pseudomonas spp. Nine varieties of Pseudomonas were found, which represented at least 3 Pseudomonas species. Many of the bacterial isolates (especially the pseudomonads) are potential pathogens in the eyes of these camelids.